Friday, April 09, 2010

First Discovery spacewalk under way

Astronauts Rick Mastracchio and Clay Anderson have switched their spacesuits to battery power, officially beginning the first of Discovery's three spacewalks at 1:31 a.m. EDT, 10 minutes ahead of schedule.

The spacewalkers flipped open the Quest airlock hatch as the International Space Station flew 216 miles over the Atlantic Ocean.

This is the 141st spacewalk supporting station assembly and maintenance, and the fourth for both Mastracchio and Anderson.

Mastracchio will begin by picking up a handle that he'll take to Discovery's payload bay and attach on ammonia tanks, so the station's robotic arm can grab hold of them. He'll release four bolts to free the tank from its carrier.

Anderson will move to the depleted tanks on the station's central truss to disconnect four ammonia and nitrogen lines. That done, he'll join Mastracchio in the payload bay and disconnect lines on the new tanks.

They'll work together to hand the 1,700-pound tank to the station robotic arm.